• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.70-78
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• 2012

In order to calculate the ecological carrying capacity of Donggung and Wolji, Gyeongju, the number and time for various activities of tourists were surveyed and then the injury tolerance on lawns was predicted with seven types of various activities. According to the injury tolerance in various activities for the suitable carrying capacity, the normal carrying capacity and the limited carrying capacity were explicitly determined in four lawns. According to the number and time for various activities, the injury tolerance of various activities was predicted in four lawns, and the highest average injury tolerance was 2.15 in walking, the lowest average injury tolerance was 0.05 in lying. The highest injury tolerance was 1.31 in lawn 4, and then the order was 0.97 in lawn 3, 0.91 in lawn1, and 0.70 in lawn 2. The ecological carrying capacity was predicted with a damaged area according to the injury tolerance of various activities. The suitable carrying capacity was done separately to 40 persons, 249 persons, 107 persons, 37 persons, the limited carrying capacity was 116, 713, 306, 107 respectively and the normal carrying capacity was 75, 463, 198, 69 in four lawns. When managed in Donggung and Wolji, Gyeongju, the number of tourists was under the limited carrying capacity, the conformation would grow better.

• Journal of Life Science
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• v.14 no.4
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• pp.614-619
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• 2004

This study was undertaken to investigate the different responses of cultured plant cells to paraquat treatment and nucleus-DNA damage in relation to enzyme activity of superoxide dismutase (SOD). Furthermore, this study was also carried out to understand the antioxidative mechanism of plant cells to environmental stress. We selected two different species of plant cultured cells, Ipomoea batatas as high-SOD species and Lonicera japonica as low-SOD species. The total activity and specific activity of SOD in a chlorophyllous cell of I. batatas were 3,736 unit/gㆍfresh weight and 547 unit/mgㆍprotein, respectively, and those in L. japonica were 23 unit/gㆍfresh weight and 13 unit/mgㆍprotein, respectively SOD activity in chlorophyllous I. batatas cells reached its maximum level at 10 to 15 days after subculture, whereas that in L. japonica remained at a very low SOD level during the whole period of subculture. In comparison to L. japonica, I. batatas, a high-SOD species, showed high tolerance to paraquat 10 and 50 mg/l treatment in terms of cell viability and electrolyte leakage. Based on the result of comet assay, the nucleus-DNA damage of two species by paraquat 50 mg/l treatment was not significantly different. However, I. batatas cells repaired their damaged DNA more effectively than the cells of the low-SOD species, L. japonica.

• Smart Structures and Systems
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• v.15 no.3
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• pp.593-608
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• 2015

In many of the industrialized countries an increasing amount of infrastructure is ageing. This has become specifically critical to bridges which are a major asset with respect to keeping an economy alive. Life of this infrastructure is scattering but often little quantifiable information is known with respect to its damage condition. This article describes how a damage tolerance approach used in aviation today may even be applied to civil infrastructure in the sense that operational life can be applied in the context of modern life cycle management. This can be applied for steel structures as a complete process where much of the damage accumulation behavior is known and may even be adopted to concrete structures in principle, where much of the missing knowledge in damage accumulation has to be substituted by enhanced inspection. This enhanced and continuous inspection can be achieved through robotic systems in a first approach as well as built in sensors in the sense of structural health monitoring (SHM).

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.99-108
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• 1995

The experiment was carried out to define the effect of the boron in nutrient solution on the development of mulberry root and cold damage. The length of shoots only attained about 50cm and then stopped in case of boron deficiency, while the mulberry trees developed vigorous and attained over 190cm long under boron supply condition. When boron is deficient, the measles appeared on surface of the stem and the necrosis appeared on the petiole, midribs and veins of leaves. At 70 days after planting, almost all new roots and old roots changed to brown, the lateral roots became necrosis by boron deficiency. After three days of stopping boron supply, many new roots changed to brown and after two days of boron resupply, new roots began to grow out and then new roots normally developed. Content of boron in leaves and barks increased by the increase of boron concentration in nutrient solution and maximum boron content in leaves and barks was obtained with boron-sufficient treatment of 0.5ppm. Treatment of 0.5ppm boron supply indicated that the leaves and barks contained more phospholipid, protein, sugar, RNA and proline than treatment of 0.01ppm boron supply in nutrient solution. The cuttings grown in boron supply nutrition have a sufficient tolerance at -10$^{\circ}C$ and -15$^{\circ}C$ for 24 hours while cuttings grown in boron-deficient nutrition have a weak tolerance at the same condition. As mentioned above, we can conclude that the effect of boron deficiency on root development is much severe and the relationship between the lack of boron and cold damage is very closely related.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1275-1282
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• 2012

Helicopter rotor systems are dynamically loaded structures with many composite components such as the main and the tail rotor blades. The fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. The safe-life methodology has generally been used in the helicopter industry to substantiate dynamically loaded composite components. However, it cannot be used to evaluate the strength reducing effects of flaws and defects that may occur during manufacturing and operational usage. The damage tolerance methodology provides a proper means to overcome this shortcoming; however, it is difficult to economically apply it to every composite component. The flaw tolerant methodology is an equivalent option to the damage tolerance methodology for civil and military rotorcraft. In this study, the flaw tolerant safe-life evaluation is described and illustrated by means of successful application to substantiate the retirement time of composite rotor blades.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.679-683
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• 2006

The effects of dried and fermented guava (Psidium guajava L.) leaf extracts on blood glucose levels were investigated in low-dose streptozotocin(STZ)-induced diabetic mice. Fermented guava leaf extract (500 mg/kg/day) significantly decreased the fasting blood glucose levels after 2-4 weeks of treatment and improved the impaired glucose tolerance in STZ-induced diabetic mice. On the other hand, dried guava leaf extract lowered the blood glucose levels and improved glucose tolerance two weeks after treatment, but exacerbated STZ-induced high blood glucose levels three and four weeks after treatment. Histological and immunohistochemical observation showed that fermented guava leaf extract treatment improved STZ-induced pancreatic beta-cell damage, but dried guava leaf extract did not affect the damage to the beta-cells. These results suggest that fermented guava (Psidium guajava L.) leaf extracts improve the hyperglycemia by protecting the pancreatic beta-cells hom damage in STZ-induced diabetic mice.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.172-178
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• 2003

This study was conducted to assess the physiological tolerance of native tree species for successful restoration and revegetation of abandoned coal-mine spoils. Study sites were two coal-mine spoils (Sododong and Ssarijae) in Taebaek, Kangwon Province, Korea. Five individuals of Betula costata and of B. schmidtii were analyzed for malondialdehyde (MDA) and hydrogen peroxide ($H_2O$$_2$) content, nitrate reductase (NR) and superoxide dismutase (SOD) activity, and for carbohydrate concentration in the leaves. Trees in the abandoned coal-mine spoils were influenced by deficiencies expressed by MDA and $H_2O$$_2$ content in the leaves of two species being higher at the coal-mine spoils than in the surrounding forest. Low NR activity indirectly represented nitrogen deficiency in the soil of the coal-mine spoils; an unmanageable SOD activity implied that tolerant functions didn't net against a certain stress of the coal-mine spoils. Decreased glucose and increased starch concentration especially showed the inhibition of the carbohydrate metabolism by inadequate factors. Consequently, low nitrogen content in the real-mine soils might increase damage in trees as a result of inhibiting the expression of tolerance mechanisms against stress. Therefore, trees in coal-mine spoils need ample nitrogen to use as a metabolic energy source in order to prevent damage and increase tolerance against stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.341-351
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• 2002

In order to examine the mechanistic basis for differential sensitivities to chilling and subsequent recovery between two rice (Oryza sativa L.) cutivars, a chilling-tolerant japonica type (Ilpumbyeo) and a chilling-susceptible indica type (Taebaekbyeo), changes of physiological responses and antioxidant enzymes were investigated. Both cultivars at 3 leaf stage were exposed at a low temperature of $5^{\circ}C$ for 3 days and subsequently recovered in a growth chamber at a $25^{\circ}C$ for 5 days with 250 mmol $m^{-2}$ $s^{-1}$. Physiological parameters such as leaf fresh weight, relative water content, cellular leakage, lipid peroxidation, and chlorophyll a fluorescence showed that the chilling tolerant cultivar had a high tolerance during chilling. However, the chilling-susceptible cultivar revealed severe chilling damages. The chilling-tolerant cultivar was also faster in recovery than the chilling-susceptible cultivar in all parameters examined. We analyzed the activity and isozyme profiles of four antioxidant enzymes which are: superoxide dismutase (SOD), caltalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR). We observed that chilling-tolerance was due to a result of the induced or higher antioxidant enzyme system, CAT and APX in leaves and SOD, CAT, APX, and GR in roots. Especially, we observed the most significant differences between the chilling-tolerant cultivar and -susceptible cultivar in CAT and APX activity. Also in isozyme profiles, CAT and APX band intensity in the chilling-tolerant cultivar was distinctively higher than in the chilling-susceptible cultivars during chilling and recovery. Thus, the cold stability of CAT and APX are expected to contribute to a tolerance mechanism of chilling in rice plants. In addition, the antioxidative enzymes activity in roots may be more important than in that of leaves to protect chilling damage on rice plants.

• The Korean Journal of Physiology
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• v.9 no.1
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• pp.57-61
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• 1975

A study was designed to clarify the influence of the hippocampus upon tolerance by electric shock. Forty-eight male rats were used, of which 14 rats had their hippocampal tissue on both sides removed through an opening in the parieto-occipital cortex (hippocampal group), 17 rats received damage to the parieto-occipital cortex only (cortical control group), and 17 rats served as normal control animals. After 24 hours' fasting with water ad libitum, each animal was restrained on a plate with added electric shock (4 mA A.C., 1.5 sec in a duration, and once per minute in average) to the tail for the last 24 hours without food and water. The mortality in each animal group and the mean survival time of the dead animal during the repitition of electric shock were calculated. Results obtained were as follows: 1. The mortality was lower significantly in the hippocampal group than in the two control groups. 2. The mean survival time of the dead animal was longer insignificantly in the hippocampal group than in the two control groups. The inference from the above results is that the hippocampus exerts a inhibitory influence upon tolerance by electric shock.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.818-823
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• 2012

Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by polymerase chain reaction, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops.